fix: raise Express JSON body limit to 25mb for OCR image payloads

Default 100kb limit rejected base64-encoded scanned page images
with 413 Payload Too Large, breaking /documents/ocr-image for any
realistic scan.

src/index.ts

@@ -17,7 +17,10 @@ const limiter = rateLimit({
 });
 
 app.use(cors());
-app.use(express.json());
+// Varsayılan limit (100kb) OCR için gönderilen base64 taranmış sayfa görsellerini
+// (300KB-1MB+ ham, base64 ile ~%33 daha büyük) kolayca aşıyordu ve 413 Payload
+// Too Large ile reddediliyordu — bkz. /documents/ocr-image.
+app.use(express.json({ limit: '25mb' }));
 
 // If your app is behind a proxy (like Nginx, Docker ingress, etc.),
 // the IP will default to the proxy's IP. We set trust proxy to get the real client IP.